Process and device for producing expansion joints in concrete



j [@NENNWk J G. 'WIELAND Sept. 5, 1939'.

I PROCESS AND DEVICE FOR PRODUCING EXPANSION JOINTS IN CONCRETE FiledNov. 14, 1935 Patented Sept. 5, 1939 UNITED STATES PROCESS AND DEVICEFOR PRODUCING EXPANSION JOINTS IN CONCRETE Georg Wieland,Berlin-Iichterfelde, Germany Application November 14, 1935, Serial No.49,840 In Germany November 16.1934

8 Claims.

The invention relates to a process and device for the production ofexpansion joints in concrete pavements.

In the production of streets paved with concrete, the expansion jointshave been produced as narrow gaps in the pavement in order that theseparate parts of the pavement could move easily and independently. Inthe lower part of the gaps, asphalt cardboard, wooden boards, or woodenfiber sheets were inserted. The upper portion of the joints have beenprovided temporarily with insert peces of iron or the like which wereplaced with their upper edges even with the finished street surface. Assoon as the concrete had stifiened a little, the inserts were lifted outbefore the concrete had set. The edges were then smoothed. In spite ofcareful lifting of the insert pieces, the tamped concrete was alsolifted and loosened. It was impossible to restore the loosened structureof themass to its original condition of cohesion as the repairing wouldtake more time than the setting of the concrete. Thus, the concrete wasdisturbed in its process of getting hard. The consequence was that theconcrete bodies became cracked at the edges of the joints.

According to the present invention, in the production of such bodies orconstructions, insert bodies of heat conducting materials are used. Theinsert bodies are enveloped by a fusible material which gets soft orliquid upon being heated. Such insert bodies are embedded in theconcrete pavement with their upper edges even with the upper surface ofthe pavement. After the hardening of the concrete has begun, the bodiesare heated temporarily and then drawn out.

This manner of working enables the insert bodies to be drawn outinstantly after their heating while still hot. The envelope which hasbecome soft or liquid provides the necessary loosening of the embeddedinsert bodies and serves besides as a lubricant.

As melting materials for the envelope, bitumen, wax, or paramn willserve.

The insert bodies may be hollow and heated by bodies.

The invention is described in more detail in steam or hot air which ispassed through the cement shall take place without being disturbed ,Fig.3 shows an instrument for drawing out the joint inserts; and

Figs. 4 and 5 are front views in reduced scale of elongated insert bodeshaving inlet and outlet openings. 6 In the lower concrete layer 6, theexpansion joint is filled with a wooden board or wooden fiber plate I.The latter carries a holder 4 which serves for positioning and holdingthe hollow joint insert l. The joint insert member I formed of twopieces is advantageously welded together. Numerals l8 l8 indicate thewelding seams.

The joint inserts consist suitably of iron, aluminum or other metal.They have a trapezoidal cross-section and have a breadth, for instance,15

of 15 mm. and an inner hollow space 3 of 'a breadth of 5 mm. They areprovided with openenings I! for entrance and exit of steam. For thispurpose it may suffice that the hollow space be left open at both ends,as shown in Fig. 5, 20 or the ends may be closed and openings providedin the upper edge, as shown in Fig. 4. Before the insert body is put inplace, it is provided with a bituminous film 2, for instance of asphaltbitumen, on its outer surfaces. Then it is placed 25 in the holder 4.The upper concrete layer 5 is then formed by tamping or rolling. Thejoint insert l remains embedded when the concrete has set and becomehard. After a period of, for instance, two or three days, steam or hotair is passed through the hollow space of the joint insert I. At about55 C. the bituminous fllm becomes liquid and the joint insert can beeasily drawn out. The bitumen is then absorbed by the concrete wall.Thus the painting of the concrete wall is saved, so that the joint canbe filled immediately with bituminous material.

In the'production of the upper concrete layer 5, the joint insert I maybe completely embedded. 40 By heating the insert body, the thin concretecovering over the joint insert breaks oil automatically and in astraight line. v

As seen in Fig. 2, the joint insert may be placed with its upper edgeeven with the finished pavement and the edges of the joints may berounded with the aid of a suitable masons trowel.

The use of insert bodies with two hollow spaces according to Fig. 2enables letting steam in and out at the same end. When using solidinsert bodies, the heating may take place electrically.

The insert bodies may also be pressed into the concrete masses, when thelatterare formed. It is... only essential that the initial setting ofthe lever l grips into the space H of the joint insert 1, Whilst theother gripping lever carries a movable part l2 which is provided with ahandle ,8, a bore l3 and a shutting valve M. Part l2 seats in the cavity16 of the joint insert I. Into the solidly constructed edge part l5 ofthe joint insert leads achannel I! from the cavity I6 to the inner spaceof the joint insert.

When the tongs are placed in position, the valve I4 is opened and thesteam from a steam lead connected thereto passes into the joint insert.When the latter is heated sufficiently, the valve lfi'is closed and thejoint insert may be pulled out with the aid of the tongs.

As the jointinsert is ;completely loosened by heating and lies separatedin the concrete mass before it is drawn out, the joint insert may haveany shape, for instance a zig-zag-, arch-, or S-form. In this wayexpansion joints may be produced,- over which the wheels of a vehiclealways roll on after another. The joints can be produced of any depth.

In the claims:

1. Process of forming expansion joints in conorete pavements comprisingforming the pavement with insert bodies of heat conducting materialhaving their side walls covered with fusible material embedded in thepavement with their upper edges substantially even with the uppersurface of the pavement, heating the insert body for a short time toabove the fusing point of the fusible covering material after theconcrete has become hard, and withdrawing the insert body from thepavement when its covering has become fused.

2. Expansion joint insert body for use in concrete pavements comprisinga closed, hollow metallic body having an entrance opening and adischarge opening for a hot fluid, and having a coating of bitumen onits outer surface.

GEORG WIELAND.

